1. Field of the Invention
The invention pertains to a three way valve having a positive shut off valve for mixing or diverting a flowable material. More particularly, the novel hygienic three way valve is provided for mixing or diverting flowable materials while avoiding contamination of the flowable material by employing a positive controlled valve having a tapered valve seat of a substantially frustro-conical configuration in combination with a substantially cylindrical piston sealing head actuated by a piston positively controlled by fluid activation.
The fluid activated piston of the novel hygienic three way valve preferably employs a pneumatically controlled piston having a pneumatic activation chamber at one end and a product chamber at the other end. The pneumatically activated piston is disposed through the valve body, which valve body includes a leak detection port disposed between the pneumatic activation chamber and the product chamber with a first sealing means disposed between the leak detection port and the pneumatic activation chamber and a second sealing means disposed between the product chamber and the leak detection port.
The leak detection port, in combination with the first and second sealing means not only provides early detection of seal failure but also identifies the location of the defective seal without allowing contamination of the fill material with contaminants in the pneumatic air or activation fluids in the chamber for activating the positive controlled piston. The combination of the air or fluid in the activation chamber with cups on the piston allows the piston to not only positively open and close the valves, but also to assume an infinite number of positions between the valves.
The novel hygienic three way valve not only prevents contamination of the flowable fill material with the fluids used to activate the positive controlled piston for opening and closing the positive control valve, but also provides for the mixing or diversion of fluids introduced to the three way valve by utilizing a second tapered valve seat having a substantially frustro-conical configuration disposed axially adjacent to the first tapered valve seat to utilize both an upper and lower portion of the substantially cylindrical piston sealing surfaces of the sealing head attached to the positively controlled piston.
The first and second tapered sealing seats are disposed in a mixing or diversion chamber disposed below an inlet chamber communicating with a product introduction port. A second port communicates with the mixing or diversion chamber intermediate the first and second sealing seats to provide a mixing or diversion chamber which also communicates with an outlet port. The novel hygienic three way valve is preferably segmented into a fluid cylinder or chamber for housing the positive controlled piston activation means, a main body, having a first or inlet product chamber and a second or product mixing or diversion chamber, and a port disposed intermediate the tapered ends of the mixing or diversion chamber and an outlet port in axial alignment with the mixing or diversion chamber.
The novel three way hygienic valve includes, in the preferred application, flanged connections between the fluid activation chamber, the main body of the three way valve, and the outlet port. In addition, flanges are provided for interconnections between the first inlet port leading to the first product chamber and the product port communicating with the second product chamber, as well as at both ends of the outlet port. Optionally, the main body can be further segmented and additional flange connections can be provided between the first product chamber and the second product chamber, as well as the provision of additional mixing chambers along the axial length of the sealing piston, as well as additional sealing heads of decreasing diameters disposed axially along the length of the novel hygienic valve. The combination of axial aligned sealing heads in such applications can provide a plurality of mixing and/or diversion zones in the novel valve, as well as providing a positive shut off of all of the mixing chambers from the outlet nozzle by the retraction of the positively controlled piston for controlling multiple valves.
The novel hygienic mixing or diversion valve of the invention may include a plurality first and second seals for providing a determination of seal failure and a plurality of leak detection ports between the various axially aligned mixing or diversion chambers. The novel hygienic three way valve is preferably constructed of a seamless material, such as stainless steel, glass or other material that can be easily cleaned and has a smooth, seamless surface that prevents the build-up of bacteria or other contaminants that would have a deleterious effect upon fill products requiring the highest hygienic handling consistent with food, medical and pharmaceutical preparations and processing.
2. Description of Related Prior Art
A wide variety of product mixing or diversion valves are known in the prior art. Some of these diversion valves are made of stainless steel, glass and other seamless materials, but these prior art diversion valves do not include a positive shutoff valve provided by a pneumatically activated piston having a sealing head of a substantially cylindrical configuration in combination with a pair of tapered sealing seats of a frusto conical configuration in combination with a leak detection port for providing a positive identification of seal failure before deterioration of the seal has resulted in contamination of a fill product with the fluid for activation of the piston.
In the prior art, seal failure has resulted in the contamination of the fill product with the fluids for activating the product valve piston. The fluids typically utilized in the food processing industry have been partially pneumatically controlled and partially spring controlled pistons and when such prior art pistons fail, the fill product is contaminated with pressurized air from an air pressure source and the contaminants generally found in pressurized air which typically include dust, bacteria, oil and other small particulate matter as well as lubricants employed with springs in the piston activation chamber. Typically, such seal failures have resulted in shutting down the production line and in some cases, recall of defectively packaged products.
None of the know prior three way mixing and diversion valves have provided a positive leak detection means for providing advanced warning of a seal failure or provided a failsafe seal that would prevent the contamination of the fill product with the pneumatic fluid pressure and spring combination for operating the product dispensing piston. Further, none of the known prior art utilizes a positive control valve in combination with the pneumatic piston, which provides a tapered seat for positively controlling the dispensation of a fill product without displaying some dripping or bleed through of product around the piston. Such problems are common in the food processing industry, where stainless steel pistons are typically utilized to exert pressures on compressible fluids utilized to dispense a flowable product which is obviated by the present invention in allowing the piston to free float and not compress the fluid when the piston is operated in applications where closure of one of the valves is not required. Further in the prior art stainless steel pistons have not utilized a rubber or an elastomeric sealing head in combination with tapered sealing seats disposed in the path of flow of the dispensed flowable product.
In a prior art search no patents were uncovered utilizing a novel three way valve similar to that of the present invention with a leak detection port. Instead prior art was uncovered pertaining to leak detection ports and devices and three way valves. The most relevant prior art pertinent to leak detection ports pertained to leak detection devices used in gas flow applications such as Matthews U.S. Pat. No. 3,999,932, Kurtz, et al U.S. Pat. No. 4,648,874 and Steeper et al U.S. Pat. No. 4,888,979. None of these prior art leak detection patents teach or suggest the utilization of a leak detection port in combination with a product mixing or diversion valve.
None of the known prior art leak detection port devices employs a double seal arrangement in combination with a mixing or diversion valve piston to prevent the contamination of a processed product. The closest known prior art is Steeper U.S. Pat. No. 4,888,979, which discloses a leak detection port across an O-ring flanged connection. The leak detection port provided in Steeper U.S. Pat. No. 4,888,979 pertains to a leak detection port for indicating leaks radially along the O-ring as opposed to axially along the length of the piston as is provided in accordance with the novel fill valve assembly of the invention.
The most relevant patent uncovered pertaining to diverter or three way valves in the prior art most pertinent to the present invention is Copas, et al U.S. Pat. No. 4,518,021 which pertains to a machine for filling containers which, like the present invention, provides for the flanged connections for the various components. Copas, et al U.S. Pat. No. 4,518,021 in col. 8, lines 6-19, describes the utilization and operation of the diverter valve but does not describe the diverter valve other than to describe it as manually operable. The other prior art patents uncovered pertinent to three way valves include Fujioka U.S. Pat. No. 5,535,923, Yonezawa U.S. Pat. No. 5,082,021, Spencer U.S. Pat. No. 4,306,586 and Anderson U.S. Pat. No. 4,535,821. These prior art patents include provisions for directing fluids from port to port without contamination, pressure activated piston valves and beverage pouring apparatus. However, each of the valve devices are patently distinct from the novel three way valve of the invention.
The invention pertains to a novel three way valve, particularly suited for applications involving the mixing or diversion of flowable products requiring hygienic treatment, such as are encountered in the pharmaceutical, medicinal and food handling industries. More particularly, the novel three way valve provides positive control over mixing and diversion of fluid materials by employing a positive control pneumatically activated valve formed by a piston having a substantially cylindrical head in combination with one or more tapered seats for cooperating with the substantially cylindrical head to provide precise control over fluid products, such as medicine formulations, milk, yogurt and other dairy products and beverages. The novel three way valve is positively controlled by air pressure to open or close each valve but also can utilize differential pressures in the piston activation chamber to free float between the tapered valve seats when desired. The novel three way valve is preferably composed of stainless steel or other material that is substantially free from threads, seams, welds or other surface imperfections that would foster the growth of bacteria or other deleterious substances.
The novel three way valve utilizes a fluid activated piston for positively mating in at least one valve seat to form a valve provided by the combination of the substantially cylindrical sealing head of the piston, in combination with at least one tapered sealing seat in the novel three way valve. In the preferred application, a pair of tapered sealing seats in axial alignment are provided in the novel three way valve to provide a first and second valve by cooperating with a double sided sealing head of the piston by utilizing the bottom of the substantially cylindrical piston head and the top of the substantially cylindrical head in response to the pneumatic activation of the mixing valve piston. The mixing valve piston with the substantially cylindrical piston head, can be operated to maintain the substantially cylindrical piston head intermediate the axially aligned tapered sealing seats by utilizing differential air pressure in the piston activation chamber in relation to the density of the processed fluid product to provide a turbulence generating mechanism to assist in the mixing of fluid in the mixing valve embodiment of the novel product three way valve.
The novel product three way valve is preferably composed of a main valve body, a pneumatic chamber for activating the product valve piston and an outlet port having a tapered seat for providing one of the tapered seats for the novel three way valve. The main body includes, at one end, a flange for mating with a corresponding flange of a pneumatic chamber or cylinder for activating the pneumatically controlled piston and at the other end, a flange for accommodating the product outlet containing one of the tapered sealing seats for the pneumatically controlled piston. The novel product three way valve includes at least two product input ports for receiving products to be either mixed or diverted in the novel three way product valve.
The novel three way product valve is particularly adapted for hygienic filling and mixing operations and includes a leak detection port for identifying the precise position of a defective seal before products introduced into the novel three way valve can become contaminated in filling or product diversion operations. The leak detection port is provided in the novel three way valve in the main valve housing at a point intermediate the attachment of the piston valve actuating chamber and a first product chamber disposed in the novel three way valve body. A first seal is provided intermediate the first product chamber and the leak detection port and a second seal is provided intermediate the leak detection port and the pneumatic piston activation chamber. The leak detection port in combination with the seals provides a positive identification of the location of a defective seal as being either the first or the second seal and at the same time, prevents contamination of either the processed product or the pneumatic air chamber by utilizing the other seal as a failsafe system to prevent bypass of air or product to prevent contamination.
The novel three way valve main body includes a first product processing chamber in axial alignment with a second processing chamber and a first tapered sealing seat intermediate the first product chamber and the second product chamber. A first port communicates with the first product processing chamber and a second port communicates with the second product processing chamber. The product processing piston with the sealing head is designed to be positioned in at least two different positions in the second product processing chamber and provide closure of the first product processing chamber from the second processing chamber by seating in the first tapered sealing seat or to seal the second tapered sealing seat at the other end of the second product processing chamber. Alternatively, the product processing piston is also designed to operate to either free float or be positively controlled by air in piston activation chamber to assume positions intermediate the first and second tapered sealing seats in the second product processing chamber to assist in the mixing or diversion of fluids in the second product processing chamber.
The novel three way valve not only provides for diversion and mixing of fluids in the processing chamber, but also provides for the hygienic handling of fluid material, such as medicinal products, food products, beverages and other fluid materials by preventing the contamination of processed products with the fluid utilized to activate the pneumatic piston. Flanges connecting the components assist in cleaning and maintenance operations which, together with the composition of the stainless steel used for the construction of the valve, assists in cleaning operations. The positive identification of deterioration of the seal prevents the packaging and possible shipment of contaminated product, which would subsequently require expensive recall of defectively filled or contaminated packaged products.